Rails 嵌套循环依赖

Question

我有一个循环依赖的模型：

class InventoryItem < ApplicationRecord
  belongs_to :location
  belongs_to :bin

  accepts_nested_attributes_for :location
  accepts_nested_attributes_for :bin
end

class Location < ApplicationRecord
  has_many :bins
  has_many :inventory_items

  accepts_nested_attributes_for :bins
end

class Location < ApplicationRecord
  has_many :bins
  has_many :inventory_items

  accepts_nested_attributes_for :bins
end

inventory item 形式：

  <div class="field">
    <%= form.fields_for :location do |location| %>
      <%= location.label :location_name %>
      <%= location.text_field :name %>
    <% end %>
  </div>

  <div class="field">
    <%= form.fields_for :bin do |bin| %>
      <%= bin.label :bin_name %>
      <%= bin.text_field :name %>
    <% end %>
  </div>

还有 inventory item 控制器：

  def new
    @inventory_item = InventoryItem.new
    @inventory_item.build_bin
    @inventory_item.build_location
  end

  def inventory_item_params
    params.require(:inventory_item).permit(:location_id, :bin_id, location_attributes:[:name], bin_attributes:[:name])
  end

但是当我提交表单时出现错误：

Bin location must exist

我不知道在哪里或如何创建 Bin 和 Location 之间的关系，或者是否可能。

提前致谢

Answer 1

你没有循环依赖。

• 位置不依赖于创建
• Bin 依赖于位置
• InventoryItem 依赖于 bin 和位置

所以如果你按照正确的顺序创建它们

1. 位置
2. Bin（附加到位置）
3. 库存项目（两者都附加）

你应该没事。

像这样

# the nesting in params may be off but you can definitely figure this out by looking at the console log of form's request.

    # 1. Create location with name (no dependencies)
    location = Location.create({name: params[:location][:name]})

    # 2. Create bin referencing location
    bin = Bin.create({location: location, name: params[:bin][:name]}) 
  
    # 3. Create inventory item referencing both.
    @inventory_item = InventoryItem.create({bin: bin, location: location})

我不确定如何使用 accepts_nested_attributes_for 执行此操作，但如果您可以使其正常工作，那将是一个干净的解决方案。